1. Jeep Grand Cherokee Laredo 2001 4.0 02sensor heater codes.

    So after much sitting in my driveway after a failed Crank sensor, a leaking gas tank and rusted out skid plate for the gas tank, I got the ugly monster running ok. But I'm do for a NY inspection and I am getting codes related to the 02 sensors heaters. It's on all four 02 sensors and it is on the heaters side( Sorry cleared codes and didn't grab numbers). Any circuit or fuse carrying this power supply for the heaters? Thanks.

    dlm ny country

  2. #2
    Join Date
    Feb 2009
    Location
    Dayton Ohio Area
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    Jeep Grand Cherokee Laredo 2001 4.0 02sensor heater codes.

    Yes check your fuses. Check your battery too. Its unlikely all four go at once but a weak battery can cause wierd codes.

    If you replace use OEM which is NTK brand.

    Sent from my iPhone using Jeepz.com mobile app
    Last edited by JPNinPA; 02-01-2020 at 04:03 PM.
    "Never look down on anybody unless you're helping him up" - Jesse Jackson

  3. #3

    Re: Jeep Grand Cherokee Laredo 2001 4.0 02sensor heater codes.

    Thanks. With the vehicle sitting for a while (at least 4 months), the battery has taken a turn for the worst. It doesn't hold good voltage over a few days of idle parking.

  4. #4
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    Jeep Grand Cherokee Laredo 2001 4.0 02sensor heater codes.

    If you have a trickle charger you could possibly save the battery. Charging in an on a day and off a day may reverse the scaling on the plates. However If the scale is crystallized you are done.


    Regards,
    JPNinPA

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    Last edited by JPNinPA; 02-01-2020 at 10:25 PM.
    "Never look down on anybody unless you're helping him up" - Jesse Jackson

  5. #5

    Re: Jeep Grand Cherokee Laredo 2001 4.0 02sensor heater codes.

    I have a trickle charger for my 1974 BMW. I can swap it over to the Jeep for a few days. My regular battery charger has a setting for 2 amps also. Will give it a go.

    dlm ny country

  6. #6

    Re: Jeep Grand Cherokee Laredo 2001 4.0 02sensor heater codes.

    So Jeep has been getting some use but not much (don't want to get a no inspection ticket).. It still is throwing 02 heaters codes, sometimes all 4 but usually P0138, bank 1 sensor 2. It will throw it too, after a fresh start if I clear the codes, usually by itself with no other codes. Jeep is running fine otherwise(minus a Speedometer that just started cutting out sometimes). Not sure if the one sensor (Bank 1 sensor2) could be what is throwing the whole thing off. Hate to buy a sensor and then find out that wasn't the deal. Looking for input. Thanks.
    dlm ny country

  7. #7
    Join Date
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    Jeep Grand Cherokee Laredo 2001 4.0 02sensor heater codes.

    You have inspected the wiring? Do you have exhaust leaks?
    Check the fuse and relay below. Not sure 01 is the same but worth a shotThe next step would be to hook up a scanner that you could see the O2 switching. Or pull an O2
    Jeep Grand Cherokee Laredo 2001 4.0 02sensor heater codes.-img_3096.jpg Jeep Grand Cherokee Laredo 2001 4.0 02sensor heater codes.-img_3095.jpg



    Regards,
    JPNinPA

    Sent using TapTalk
    Last edited by JPNinPA; 02-17-2020 at 09:34 AM.
    "Never look down on anybody unless you're helping him up" - Jesse Jackson

  8. #8

    Re: Jeep Grand Cherokee Laredo 2001 4.0 02sensor heater codes.

    Thanks so much JPNinPA. I will give it a go when I get a chance. This weekend, I stopped clearing codes with the MIL light on. I was getting all these mixed 02 heater related codes. Funny , today I get in the WJ to go home and MIL light was off. So I checked when I got home and there were several various 02 heater related codes in memory but no MIL Light. I left it alone for now. It feels like a wire connection of some type. All the monitors haven't cleared so it still won't pass inspection.

    dlm ny country

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